Palpana

Palpana (from, ram ) is a volcano in the Andes of Chile. It has a summit elevation of 6040 m.

It is part of the dividing range between Upper Loa River basin and Salar de Ascotán basin. Together with Inacaliri and Azufre, it forms a 50 km long volcanic chain constructed along the Inacaliri lineament. The volcano rises above an ignimbrite plain that in the area reaches an altitude of 3700 m and forms a chain of volcanoes with Inacaliri.

A 1.3 x wide crater surmounts the volcano and features late lava domes. A lava dome cluster is recognizable in the central sector of the volcano, forming a flat area with a surface of 4.7 km2. The volcano contains basaltic rocks with an extrusion formed from more silicic rock. Layers of mafic andesite, scoria and some pumice extend outwards away from the central sector. The volcano rises 6023 m above its terrain and its average summit slope is 26°. The western flank underwent a collapse, leaving a 2.9 km wide and 5.9 km long scar and a deposit at the volcano's foot. Olivine and plagioclase phenocrysts are found in the andesites, the overall SiO2 content is 57.6-58.9% in samples from the southern ridge. The volcano probably formed in a short timespan, given the mountainous composition and form. Normal faults have affected the area.

The volcano is no more than 1-2 mya old, but there is no evidence of postglacial material and erosion has carved radial ridges into the volcano. Precise dating methods performed on the southeastern flank have found ages of 3.65±0.15 mya and 3.81±0.30 for lavas and scoria. The snowline altitude in the area is 5900 - 6000 m Four moraine stages are found on the mountain, with the lowest moraines on the southern flank at 4200 m altitude. Nowadays, block glaciers have been identified in the area, one of which is found at 5300 m. The mountain is also one of the headwaters of the Loa River, and water was transferred from Palpana to Antofagasta by pipeline. A minor vegetation cover of 20-25% of the surface is present.

The mountain is worshipped by pastoralist people who inhabit the surrounding land, and remnants of a sanctuary have been found on its summit.